We can use srm to securely delete files on Linux.

Install srm with

sudo apt install secure-delete

We can now securely delete files by running

srm filetodelete.txt

# srm --help
srm v3.1 (c) 1997-2003 by van Hauser / THC <vh@thc.org>

Syntax: srm [-dflrvz] file1 file2 etc.

Options:
        -d  ignore the two dot special files "." and "..".
        -f  fast (and insecure mode): no /dev/urandom, no synchronize mode.
        -l  lessens the security (use twice for total insecure mode).
        -r  recursive mode, deletes all subdirectories.
        -v  is verbose mode.
        -z  last wipe writes zeros instead of random data.

srm does a secure overwrite/rename/delete of the target file(s).
Default is secure mode (38 writes).
You can find updates at http://www.thc.org

Other links for securely erasing drives.
https://www.tomshardware.com/how-to/secure-erase-ssd-or-hard-drive